JPH09101765A - Picture processor - Google Patents

Abstract

PROBLEM TO BE SOLVED: To prevent unnaturalness such that an animation image looks like frame feed when an input picture signal is displayed by a liquid crystal display device having a frame frequency lower than its transfer rate. SOLUTION: A picture signal of one frame read out from a frame buffer 202 is multiplied by (1-α) (0<=α<1) in a multiplier 203, and sent to an adder 204. A picture signal of a preceding frame read out from a frame buffer 206 is multiplied by α in a multiplier 205, added to the present picture signal as a residual image component in an adder 204, and sent to the frame buffer 206. This processing is repeated, an animation image is smoothly displayed by sending an output of the frame buffer 206 to a display.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an image processing apparatus for obtaining an output image signal having a transfer rate different from that of an input image signal.

[0002]

2. Description of the Related Art Conventionally, an image signal sent from a computer or the like at a predetermined transfer rate (frequency) is displayed on a display device (eg, a liquid crystal display device) whose upper limit of frame display frequency is lower than the transfer rate (for example, When displaying with a ferroelectric liquid crystal device (FLCD), an image processing device as shown in FIG. 9 has been used. In FIG. 9, 101
Is a workstation (EWS) or personal computer (PC) (hereinafter referred to as PC 101), 102 is a graphic accelerator suitable for image output of the PC 101, 103 is an image processing unit, 104 is a liquid crystal display device (for example, FLCD), etc. It is a display device.

In the image processing unit 103, 105 is a halftone processing unit for performing halftone processing on the image signal from the graphic accelerator 102, 106 is a motion detection unit for detecting the motion of the halftone processed image signal, and 107 is an intermediate unit. A buffer used for the processing of the tone processing unit 105 and the motion detection unit 106, and 108 is data for outputting an image signal that has undergone halftone processing according to the motion detection information of the motion detection unit 106 in accordance with the frame display frequency of the display device 104. It is a flow control unit.

Next, the operation will be described. Digital image signal u (t) input from PC 101 at time t = t
Is input to the image processing unit 103 via the graphic accelerator 102. In the image processing unit 103, first, the halftone processing unit 105 performs processing for halftone expression using the buffer 107, and then the data is input to the data flow control unit 108 and the motion detection unit 106. . The motion detection unit 106 detects the motion of the image using the image signal of the previous frame of the buffer 107 and obtains the motion detection information.

The data flow controller 108 sends the input image signal to the display device 104 according to the motion detection information. At this time, the image signal (rewriting data) input from the data flow control unit 108 to the display device 104 is
It is limited to the image data of the part which is determined by the motion detection unit 106 to be in motion within one screen. However, when the frequency of the input image data is higher than the upper limit of the display frequency of the display device 104, the motion detection unit 106 determines that there is motion, and the amount of the image signal that needs to be rewritten is determined by the display device 104 within a certain time. It may exceed the amount of rewritable data.
In this case, the data flow control unit 108 thins out the screens that are subsequently input until there is no problem in rewriting the screen that is currently being rewritten.
The display image of 04 is prevented from collapsing.

[0006]

However, in the above-mentioned conventional method, when the frequency of the image signal sent from the computer is higher than the display frequency of the display device, the screen is thinned at irregular intervals. Therefore, in a display device in which the frequency of the input image signal and the display frequency are different, when the moving image signal is displayed, there is a drawback that the motion of the moving image is frame-by-frame and lacks smoothness. there were.

It is an object of the present invention to provide an image processing device capable of smoothly displaying a moving image even on a display device having a display frequency (rate) different from that of input image data.

[0008]

According to a first aspect of the present invention, calculation is performed using an input image signal having a predetermined transfer rate and an input image signal that is at least one screen before the input image signal in terms of time. Arithmetic processing means is provided for generating an output image signal having a transfer rate different from the above transfer rate by performing processing.

According to a ninth aspect of the present invention, first storage means for storing an input image signal, first multiplication means for multiplying an output of the first storage means by a first coefficient, and an image signal The second accumulating means for accumulating, the second multiplying means for multiplying the output of the second accumulating means by the second coefficient, and the outputs of the first and second multiplying means are added, and the added output is obtained. An adding means for inputting to the second storage means is provided.

According to a fourteenth aspect of the present invention, a plurality of accumulating means for sequentially transferring the input image signal, a plurality of multiplying means for multiplying the outputs of the accumulating means by a predetermined coefficient, and the multiplying means. And an adding means for adding the outputs of the.

[0011]

According to the first aspect of the present invention, the arithmetic processing means performs the predetermined arithmetic processing using the input image signal and the input image signal of one or more screens before, so that the input image signal is different from the input image signal. An output image signal at the transfer rate can be obtained. Therefore, by synchronizing the transfer rate of the output image signal with the display frequency of the display device, a moving image with natural movement can be displayed.

According to the invention of claim 9, the input image signal of the first accumulating means and the output of the second accumulating means are respectively multiplied by the first and second coefficients, and the respective multiplication outputs are added. By repeating the processing described above at regular time intervals, it is possible to give the second storage means a time response characteristic. Therefore, by reading the output of the second storage means in synchronization with the frame frequency of the display device, it is possible to display a moving image with natural movement.

According to the fourteenth aspect of the present invention, a plurality of accumulating means are connected in series so that image signals are sequentially transferred at regular time intervals, and the output of each accumulating means has a predetermined coefficient. By multiplying and adding each multiplication output,
It can be time-responsive. Therefore, a natural moving image can be displayed by displaying the added output in synchronization with the frame frequency of the display device.

[0014]

DESCRIPTION OF THE PREFERRED EMBODIMENTS In an embodiment of the present invention,
When displaying a moving image signal on a display device having a display frequency different from the transfer rate of the input image signal, in order to display the moving image signal smoothly, the frame buffer and this frame buffer have time response characteristics,
That is, means for adding an afterimage effect is provided.

A first method for giving the frame buffer a time response characteristic is to output the frame buffer by a first coefficient and input image data by a second coefficient. The sum is used as the input to the frame buffer, and this is repeated at regular intervals. Then, the output of the frame buffer is synchronized with the display frequency of the display device and transferred to the image processing block. Here, the sum of the first coefficient and the second coefficient is 1, and in the method, the first coefficient corresponds to the time constant.

A second method for providing the frame buffer with a time response characteristic is to provide a plurality of frame buffers in front of the image processing section, and output the first frame buffer to the second frame buffer at regular time intervals. To the image processing section in synchronism with the display frequency of the display device as a display signal obtained by multiplying the first and second frame buffer outputs by respective coefficients and adding them. Here, the sum of all the coefficients is 1, and in this method, the Z conversion of the coefficients corresponds to the time constant.

FIG. 1 shows an embodiment of the present invention. In FIG. 1, reference numerals 101 to 108 are substantially the same as the same reference numerals in FIG. 9, and duplicate description will be omitted. 109 is a frequency conversion device as an image processing device according to the present invention,
Graphic accelerator 102 and image processing unit 103
It is provided between and.

FIG. 2 shows a first embodiment of the frequency converter 109. In FIG. 2, 201 is an input terminal of the digital image signal u (t), 202 and 206 are frame buffers, 203 and 205 are coefficients (1-α), a multiplier with α (α ≦ 1), and 204 is an adder. Is.

Next, the operation will be described. Digital image signal u (t) input from PC 101 at time t = t
The (pixel) is accumulated in the frame buffer 202 of the frequency conversion device 109 via the graphic accelerator 102. The pixels u (t) accumulated in the frame buffer 202 are sequentially read out and multiplied by a coefficient (1-α) in the multiplier 203 (where 0 ≦ α <1). The output (1-α) u (t) of the multiplier 203 is input to the adder 204, is added to the display output (afterimage signal) corresponding to the input image signal at time t = t−1, and is the latest display output. Is stored in the frame buffer 206.

The pixels accumulated in the frame buffer 206 are displayed as a display output corresponding to the input signal at time t = t.
The image is read at a speed according to the frame rate (display frequency) of the display device 104, and the image processing unit 103 and the multiplier 205 are read.
Entered as Time t = t input to the multiplier 205
The display output corresponding to the input signal of is multiplied by the coefficient α,
It is input to the adder 204 again and added as an afterimage signal to the processed signal (1-α) u (t + 1) corresponding to the input image signal at time t = t + 1. As a result, afterimages can be added to the image signal u (t) to be displayed as shown in FIG.

In FIG. 3, when the value of α is increased (close to 1), the afterimage added is increased.
Output for the input image signal shown in (a) (FIG. 3 (b))
Has an effect that the rising edge and the falling edge become dull and the moving image becomes smooth. On the other hand, if the afterimage added increases, spatial high-frequency components such as motion components of the image signal are canceled out, and the image has a characteristic of being blurred.

Accordingly, the display device 10 such as a liquid crystal display device (for example, FLCD) in which the frequency of the output (display) image signal is lower than the frequency of the input (displayed) image signal.
When applied to 4, the phenomenon that the smoothness of the visual moving image is insufficient due to the thinning of the screen because the moving image cannot be rewritten in time is referred to as the visual smoothness of the moving image and the blurring degree of the image. If the afterimage amount of the frequency conversion device 109, that is, the value of α (0 <α <1) is appropriately set so that the above-mentioned afterimage is added (u (t) → F
By performing (t)), a moving image that is visually smoother can be realized.

Here, F (t) = αF (t-1) + (1-α) u (t) (1) Also, comparing α ₁ <α <α ₂ and the time level characteristics of F (t), when α = α ₁ , both rising and falling are faster than when α = α ₂ , and therefore, are added. The amount of afterimage is small and the image is less blurred, but the improvement in visual smoothness is also small.

FIG. 4 is a block diagram showing a second embodiment of the frequency converter. In FIG. 4, 401 is an input terminal for the digital image signal u (t), 402, 403,
Reference numeral 404 is a frame buffer, 405, 406 and 407 are multipliers with coefficients K0, K1 and K2, and 408 is an adder.

Next, the operation will be described. The digital image signal u (t) (pixels) input from the input terminal 401 at time t = t in a constant cycle is stored in the frame buffer 402.
Is accumulated in Also, the data accumulated in the frame buffer 402 before the data is input from the input terminal 401 to the frame buffer 402 is transferred to the frame buffer 403. Similarly, the frame buffer 403
The data stored in the frame buffer 404 is transferred to the frame buffer 404. Frame buffers 402, 403, 404
The pixels accumulated in the memory are read out at a speed corresponding to the frame rate of the display device 104, and are respectively multiplied by multipliers 405 and 40.
6 and 407, the signals are multiplied by the coefficients K0, K1 and K2, and then added by the adder 408. This adder 408
The output expressed by the following equation is input to the image processing unit 103.

[0026]

(Equation 1)

In the case of the present embodiment, the time attenuation characteristic of the displayed image can be set as the Z transform (discrete Laplace transform) of the coefficients K0, K1 and K2. Increasing the values of the coefficients K0, K1 and K2 has the effect of increasing the afterimage component and smoothing the displayed moving image, while having the effect of blurring the input image signal. In addition, the correlation between the current input image signal and the image signal (pixel) that is a spatially equal value obtained by multiplying the coefficients K0, K1, and K2 is generally U than the output U0 of the frame buffer.
Since it becomes lower in the order of U2 than 1 and U1, the coefficients K0 and K
When 1 and K2 are the same value, the afterimage effect is K0 <K
While increasing in the order of 1 <K2, the coefficient K2 has the greatest influence on the blur of the image.

In order to maintain the sharpness of the image (to minimize blurring), the past image signal U having a low correlation with the current image is used.
2, it is necessary to reduce the ratio of U1 components, so K
By setting each coefficient as 0 ≧ K1 ≧ K2, it is possible to realize a moving image in which the smoothness of the moving image and the smoothness of the moving image and the blur are balanced. Also, depending on the requirements, the case where the smoothness of the movement is emphasized and the sharpness of the image (blur)
It is also possible to arbitrarily change the coefficients K0, K1, and K2 independently in the case of emphasis.

Next, an example of a method of setting the coefficients K0, K1 and K2 in the case where the sharpness of the image is emphasized in the present embodiment will be described. Since it is necessary to reduce the ratio of the components of the past image signals U2 and U1 that have a low correlation with the current image, the coefficient K is set so that the motion of the image is smoothed to some extent.
Adjusting (selecting) the smoothness of the image (the amount of afterimage to be added) within a range not more than the upper limit of the allowable image blur by adjusting 0 and then finely adjusting the coefficients K1 and K2. You can

Therefore, a liquid crystal display device (for example, FLC
When a display device in which the frequency of the output (displayed) image signal is lower than the frequency of the input (displayed) image signal as in D) is used, the screen rewriting of the display device cannot be done in time and the screen signal In order to solve the problem that the smoothness of the motion of the image is insufficient because the thinning is performed, the values of the coefficients K0, K1, and K2 are independently adjusted appropriately in FIG. 4 to increase or decrease the afterimage component to be added. Thus, it is possible to provide the image displayed on the display device with a smoothness required for the movement, and at the same time, it is possible to arbitrarily control the balance with the blur of the image generated by adding the afterimage.

FIG. 5 is a block diagram showing a third embodiment of the frequency converter 109. In FIG.
Is an input terminal for the digital image signal u (t). 502, 5
06 and 512 are frame buffers, 503, 505, and 5
07, 509, 511 and 513 are coefficients (1-α ₁ ),
Multipliers with (α ₁ ), A ₁ , (1-α ₂ ), (α ₂ ), and A _2, and adders 504, 508, and 510.

Next, the operation will be described. The digital image signal u (t) (pixels) input from the input terminal 501 at time t = t in a constant cycle is stored in the frame buffer 502.
Is accumulated in Next, the data is read at a speed corresponding to the frame frequency of the display device 104, and is multiplied by the coefficients (1-α ₁ ) and (1-α ₂ ) in the multipliers 503 and 509. Multiplier 50
The outputs of 3, 509 are input to the adders 504, 510. On the other hand, pixel data corresponding to the input signal at time t = t−1 is read from the frame buffers 511 and 512, multiplied by the coefficients α ₁ and α ₂ at the inputs to the multipliers 505 and 511, and the multipliers 503 and 509 are provided. Output (corresponding to the pixel at time t = t) is added by adders 504 and 511. The outputs of the adders 504 and 510 become the values of the frame buffers 506 and 512 at t = t.

The pixels read out from the frame buffers 506 and 512 are read out at the frame rate of the display device 104, and the weighting factors A ₁ and
After being multiplied by A ₂ , it is added by an adder 508 with the output of another frequency converter having the same configuration as in FIG. here,
Reference numerals 503 to 506 and 509 to 512 in FIG.
The circuits have the same functions and effects as those of Nos. 3 to 206, but differ only in the coefficient α. The output of the adder 508 is input to the image processing unit 103, is subjected to halftone processing, and then is output from FIG.
Is displayed on the display device 104.

Here, the output Fi of the adders 507 and 513 is Fi.
(T) and the display output F are shown by the following equations.

[0035]

(Equation 2)

In the present embodiment, the time decay characteristics of each pixel to be displayed are determined by the time constant determined by α ₁ and α ₂ and the weighting factors A ₁ and A ₂ , respectively. The weighting coefficient (attenuation component) of the output of each frequency converter having the same configuration as that in 2 can be set arbitrarily, and the time level characteristic can be set freely in the entire circuit of FIG.

FIG. 6 shows an example of attenuation characteristics according to the embodiment of FIG. Frame buffer 502 of FIG.
When the value of a certain pixel in the pixel changes with time as shown in FIG. 6A, the value of the pixel in the frame buffer 506 becomes as shown in FIG.
The value of the coefficient α ₁ is set so as to show a time change like f1 of (b), and the coefficient of the coefficient of the pixel of the frame buffer 512 changes so as to change like f2 of FIG. 6 (b). If the value of α ₂ is set, the frame buffer 5
Image signals (f1, f2) read from 06 and 512
Are multiplied by the coefficients A ₁ and A ₂ in the multipliers 507 and 513, and then added in the adder 508.
(C) The signal has an afterimage characteristic as shown by (F1 + F2).

In the present embodiment, 5 of FIG. 5 similar to FIG.
03 to 506 and 509 to 512, a plurality of frequency converters are set, the coefficient α _n (n: integer) is set so as to have independent afterimage characteristics, and each frequency converter having the same configuration as in FIG. At the output of the device, a coefficient multiplier and a multiplication coefficient A _n (0 ≦ A _n ≦ 0 as shown by 507 and 513 in FIG.
1 and n: integers), the outputs of the respective frequency conversion devices can be added with arbitrary weighting, and the variation of the afterimage characteristics is expanded.

Therefore, by adding the frequency conversion device of FIG. 5 in front of the image processing unit 103 of FIG. 1, a plurality of afterimage addition characteristics can be added at an arbitrary ratio to form an afterimage characteristic. The amount of afterimage to be added (time level characteristic shown in FIG. 6) can be precisely adjusted. Therefore, when a display device (for example, FLCD) in which the frequency of the output (displayed) image signal is lower than the frequency of the input (displayed) image signal is used, the screen rewriting of the display device cannot be rewritten in time. Then, since the afterimage is added by the above method to the phenomenon that the smoothness of the visual moving image is insufficient because the thinning of the image signal is performed, the visual smoothness of the image is realized, and It is possible to realize an afterimage addition (afterimage time level) characteristic that minimizes blurring of an image caused by adding an afterimage.

FIG. 7 is a block diagram showing a fourth embodiment of the frequency converter. In FIG. 7, 701 is an input terminal for the digital image signal u (t), 702 and 706 are frame buffers, and 703 and 705 are coefficients (1-
α _n ), α _n with a multiplier (α _n ≦ 1), 704 with an adder, 707 with a coefficient α _n by comparing the input signal u (t) with the luminance signal component of the display output F (t). Is a microcomputer that controls the value of.

Next, the operation will be described. Input terminal 70
The digital image signal u input from 1 at time t = t
(T) (pixels) are temporarily stored in the frame buffer 702.
Is done. Pixels accumulated in this frame buffer 702
u (t) is sequentially read out and the coefficient is calculated by the multiplier 703.
(1-α_n) Is multiplied (where 0 ≦ α_n<1). This
Output of the multiplier 703 of (1-α _n) U (t) is the adder 7
04, corresponding to the input image signal at time t = t-1
Display output (afterimage)
And stored in the frame buffer 706. Frame bag
The pixels accumulated in the output 706 are input signals at time t = t.
The corresponding display output is the frame of the display device 104 of FIG.
The image processing unit 10 reads out at a speed according to the frame rate.
3 and the multiplier 705. Input to multiplier 705
The display output corresponding to the input signal at time t = t
α_nIs multiplied by and input to the adder 704 again at time t
= T + 1 processed image signal corresponding to the input image signal (1-
α_n) U (t + 1) is added (an afterimage is added).

The above processing is performed on the input digital image signal u (t), and the microcomputer 707 uses the equation (6),
Input / output signals u (t), F under the conditions shown in (7)
If the luminance signal level of (t) is determined and the value of the coefficient α _n is changed according to the result, the amount of afterimage added to the image signal u (t) to be displayed is changed according to the input image. It can be changed.

[0043]

(Equation 3)

That is, since it is possible to change the rising and falling curves of the edge of the image to be displayed in accordance with the input image signal, the rising and falling curves of the edge of the image to be displayed can be changed. It can be changed according to the image signal. For example, α ₁
By selecting the value of α _n under the conditions shown in the above equations (6) and (7) as <α _2, as shown in FIG. 8, the edge of the image rises early and the edge falls late. It is also possible to frequency-convert the input digital image signal so as to decrease. In FIG. 8 (b), 7, the coefficient alpha _n is, alpha ₁ <shows the output time waveform when an alpha _2, is the coefficient α _n, α _1> α
The output time waveform when it is ₂ is shown.

The time level (afterimage addition) characteristic of F (t) with respect to the value of α _n of the frequency converter of FIG. 7 corresponds to the value of α in the frequency converter (FIG. 2) of the first embodiment. This is similar to the time level (afterimage addition) characteristic of F (t).

Therefore, the level u (t) of the input image
And α according to the output level F (t-1) of the frequency converter
Since the value of can be arbitrarily changed in units of one pixel at the maximum, a display device (for example, FLCD) in which the frequency of the output (displayed) image signal is lower than the frequency of the input (displayed) image signal When displaying a moving image signal on
The phenomenon that the smoothness of the visual moving image is insufficient due to the thinning of the image signal due to the screen rewriting of the display device not being in time, It is possible to realize visual smoothness and also to realize an afterimage addition (afterimage time level) characteristic that minimizes image blur caused by adding an afterimage.

[0047]

According to the present invention, even in a display device (for example, a ferroelectric liquid crystal display device (FLCD)) having a display frequency different from that of the input image signal, a moving image signal having an input frequency higher than the display frequency of the display device is provided. Can be displayed (reproduced) naturally.

[Brief description of the drawings]

FIG. 1 is a block diagram showing an embodiment of the present invention.

FIG. 2 is a block diagram showing a first embodiment of the frequency conversion device of FIG.

FIG. 3 is a waveform diagram showing an example of a time waveform of an input / output signal of the frequency conversion device according to the first embodiment.

FIG. 4 is a block diagram showing a second embodiment of the frequency conversion device.

FIG. 5 is a block diagram showing a third embodiment of a frequency conversion device.

FIG. 6 is a waveform diagram showing an example of a time waveform of an input / output signal of the frequency conversion device according to the third embodiment.

FIG. 7 is a block diagram showing a fourth embodiment of a frequency conversion device.

FIG. 8 is a waveform diagram showing an example of time waveforms of an input signal and an output signal of the frequency conversion device according to the fourth embodiment.

FIG. 9 is a block diagram showing a conventional display device.

[Explanation of symbols]

 104 display device 109 frequency conversion device 202, 206, 702, 706 frame buffer 203, 205, 703, 705 multiplier 204, 704 adder 402, 403, 404 frame buffer 405, 406, 407 multiplier 408 adder 502, 506 512 frame buffer 503, 505, 507, 509, 513 multiplier 504, 508, 510 adder

Continuation of the front page (51) Int.Cl. ⁶ Identification number Office reference number FI Technical display location G09G 5/36 520 9377-5H G09G 5/36 520C H04N 5/937 H04N 5/93 C

Claims (17)

[Claims] 1. A transfer different from the above transfer rate by performing an arithmetic process using an input image signal having a predetermined transfer rate and an input image signal which is at least one screen earlier in time than the input image signal. An image processing apparatus comprising arithmetic processing means for generating an output image signal having a rate. 2. The arithmetic processing means is provided with multiplying means for independently multiplying the input image signal and the input image signal at least one screen before by at least one screen by a coefficient. The image processing device described. 3. The image processing apparatus according to claim 2, further comprising selection means for selecting a coefficient of the multiplication means. 4. The image processing apparatus according to claim 1, wherein the transfer rate of the output image signal is lower than the transfer rate of the input image signal. 5. The image processing apparatus according to claim 1, further comprising display means for displaying the output image signal. 6. The image processing apparatus according to claim 5, wherein the display means has a memory function of holding the displayed image for a certain period of time after displaying the image. 7. The image processing apparatus according to claim 5, wherein the display means includes a ferroelectric liquid crystal display element. 8. The image processing apparatus according to claim 1, wherein the arithmetic processing means performs a process of generating an afterimage signal of the input image signal and adding it to the input image signal. 9. A first accumulation means for accumulating an input image signal, and a first multiplication means for multiplying an output of the first accumulation means by a first coefficient.
And a second accumulating means for accumulating an image signal, and a second accumulating means for multiplying an output of the second accumulating means by a second coefficient.
And an adding means for adding the outputs of the first and second multiplying means and inputting the added output to the second accumulating means. 10. A control means for setting the first and second coefficients used in the first and second multiplication means in accordance with the outputs of the first and second storage means, respectively. The image processing apparatus according to claim 9, which is characterized in that. 11. The image processing apparatus according to claim 9, further comprising display means for displaying an output image signal of the second storage means. 12. The image processing apparatus according to claim 11, wherein the display means includes a ferroelectric liquid crystal display element. 13. The image processing apparatus according to claim 9, wherein the second storage means reads out at a transfer rate lower than the transfer rate of the input image signal. 14. A plurality of accumulating means for sequentially transferring an input image signal, a plurality of multiplying means for multiplying outputs of the respective accumulating means by a predetermined coefficient, respectively, and an addition for adding outputs of the respective multiplying means. And an image processing apparatus. 15. The image processing apparatus according to claim 14, further comprising display means for displaying the output image signal of the adding means. 16. The image processing apparatus according to claim 15, wherein the display means includes a ferroelectric liquid crystal display element. 17. The output image signal having a transfer rate lower than the transfer rate of the input image signal is read out from the plurality of accumulating means.
The image processing apparatus according to any one of the preceding claims.